Drupal 6 JavaScript and jQuery - Ebook-Cours.com

Working with JavaScript in Drupal
How Drupal handles JavaScript
How is JavaScript typically used? Mostly, it is used to provide additional functionality
to a web page, which is usually delivered to a web browser as an HTML document.
The browser receives the HTML from the server and then begins the process of
displaying the page. During this parsing and rendering process, the browser may
request additional resources from the server such as images, CSS, or Flash. It then
incorporates these elements into the document displayed to the user.
In this process, there are two ways that JavaScript code can be sent from the server to
the browser. First, the code can be placed directly inside the HTML. This is done by
inserting code inside the and tags:
alert('hello world');
This is called including the script inline.
Second, the code can be loaded separately from the rest of the HTML. Again, this is
usually done using the and tags. However, instead of putting
the code between the tags, we use the src attribute to instruct the browser to retrieve
an additional document from the server.
In this example, src="some/script.js" points the browser to an additional script
file stored on the same server as the HTML document in which this script tag is
embedded. So, if the HTML is located at http://example.com/index.html, the
browser will request the script file using the URL http://example.com/some/
script.js.
The tag is required
When XML was first standardized, it introduced a shorthand notation
for writing tags that have no content. Instead of writing , one
could simply write . While this notation is supported by all modern
mainstream browsers, it cannot be used for
tags. Some browsers do not recognize and expect that any
tag will be accompanied by a closing tag even if
there is no content between the tags.
If we were developing static HTML files, we would simply write HTML pages
that include tags anytime we needed to add some JavaScript
to the page. But we're using Drupal, not static HTML, and the process for adding
JavaScript in this environment is done differently.
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This material is copyright and is licensed for the sole use by Richard Ostheimer on 18th June 2009
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